Lafarge will report a solid rise in first half sales on Thursday before markets open as good weather and an improved pricing environment sustain the performance from a very strong first quarter, analysts said.  They predict the April 1 price increases introduced in a series of key markets for Lafarge will offset a lower positive volume effect than that experienced in the first three months.  The US, which makes up about 28 pct of sales, should still see a strong trend in volumes though, they said, particularly in light of guidance from Mexico’s Cemex for 11 pct EBITDA growth in the second quarter.